Liquid phase alkylation process

ABSTRACT

The present invention provides a process for producing a monoalkylated aromatic compound comprising the step of contacting an alkylatable aromatic compound with an alkylating agent in the presence of a catalyst composition under effective alkylation conditions, said catalyst composition comprising MCM-56 and a binder, such that the crystal/binder weight ratio in the catalyst composition is from above 20/80 to about 80/20.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of, and claims priority toand the benefit of U.S. application Ser. No. 13/076,799, filed Mar. 31,2011 now U.S. Pat. No. 8,334,419; which is a continuation of U.S.application Ser. No. 12/835,180, filed Jul. 13, 2010, now U.S. Pat. No.7,939,700; which is a continuation of U.S. application Ser. No.11/820,907, filed Jun. 21, 2007, now U.S. Pat. No. 7,790,940, thedisclosures of which are fully incorporated herein by reference. Thisapplication also claims priority to and the benefits of U.S. ProvisionalApplication No. 61/535,632, filed Sep. 16, 2011, and EP 11188529.9,filed Nov. 10, 2011, International Application No. PCT/US2012/51181,filed Aug. 16, 2012, the disclosures of which are fully incorporated byreference.

BACKGROUND

The present invention relates to an improved process for producingalkylaromatics, for example, ethylbenzene, cumene and sec-butylbenzene.

Of the alkylaromatic compounds advantageously produced by the presentimproved process, ethylbenzene and cumene, for example, are valuablecommodity chemicals which are used industrially for the production ofstyrene monomer and coproduction of phenol and acetone respectively. Infact, a common route for the production of phenol comprises a processwhich involves alkylation of benzene with propylene to produce cumene,followed by oxidation of the cumene to the corresponding hydroperoxide,and then cleavage of the hydroperoxide to produce equimolar amounts ofphenol and acetone. Ethylbenzene may be produced by a number ofdifferent chemical processes. One process which has achieved asignificant degree of commercial success is the vapor phase alkylationof benzene with ethylene in the presence of a solid, acidic ZSM-5zeolite catalyst. Examples of such ethylbenzene production processes aredescribed in U.S. Pat. No. 3,751,504 (Keown), U.S. Pat. No. 4,547,605(Kresge) and U.S. Pat. No. 4,016,218 (Haag).

Another process which has achieved significant commercial success is theliquid phase process for producing ethylbenzene from benzene andethylene since it operates at a lower temperature than the vapor phasecounterpart and hence tends to result in lower yields of by-products.For example, U.S. Pat. No. 4,891,458 (Innes) describes the liquid phasesynthesis of ethylbenzene with zeolite beta, whereas U.S. Pat. No.5,334,795 (Chu) describes the use of MCM-22 in the liquid phasesynthesis of ethylbenzene. The latter patent teaches use of catalystcomprising MCM-22 crystalline material and binder in the ratio ofcrystal/binder of from about 1/99 to about 90/10.

Cumene has for many years been produced commercially by the liquid phasealkylation of benzene with propylene over a Friedel-Craft catalyst,particularly solid phosphoric acid or aluminum chloride. More recently,however, zeolite-based catalyst systems have been found to be moreactive and selective for propylation of benzene to cumene. For example,U.S. Pat. No. 4,992,606 (Kushnerick) describes the use of MCM-22 in theliquid phase alkylation of benzene with propylene.

Other publications show use of catalysts comprising crystalline zeolitesand binders for conversion of feedstock comprising an alkylatablearomatic compound and an alkylating agent to alkylaromatic conversionproduct under at least partial liquid phase conversion conditions. Theseinclude U.S. 2005/0197517A1 (Cheng) showing use of a catalystcrystal/binder ratio of 65/35 and 100/0; U.S. 2002/0137977A1(Hendriksen) showing use of a catalyst crystal/binder ratio of 100/0while noting the perceived negative effect of binders on selectivity;U.S. 2004/0138051A1 (Shan) showing use of a catalyst comprising amicroporous zeolite embedded in a mesoporous support, where thezeolite/support ratio is from less than 1/99 to more than 99/1,preferably from 3/97 to 90/10; WO 2006/002805 (Spano) teaching use of acatalyst crystal/binder ratio of 20/80 to 95/5, exemplifying 55/45; U.S.Pat. No. 6,376,730 (Jan) showing use of layered catalyst crystal/binderof 70/30 and 83/17; EP 0847802B1 showing use of a catalystcrystal/binder ratio of from 50/50 to 95/5, preferably from 70/30 to90/10; and U.S. Pat. No. 5,600,050 (Huang) showing use of catalystcomprising 30 to 70 wt. % H-Beta zeolite, 0.5 to 10 wt. % halogen, andthe remainder alumina binder.

Existing alkylation processes for producing alkylaromatic compounds, forexample, ethylbenzene and cumene, inherently produce polyalkylatedspecies as well as the desired monoalkyated product. It is thereforenormal to transalkylate the polyalkylated species with additionalaromatic feed, for example benzene, to produce additional monoalkylatedproduct, for example ethylbenzene or cumene, either by recycling thepolyalkylated species to the alkylation reactor or, more frequently, byfeeding the polyalkylated species to a separate transalkylation reactor.Examples of catalysts which have been used in the alkylation of aromaticspecies, such as alkylation of benzene with ethylene or propylene, andin the transalkylation of polyalkylated species, such aspolyethylbenzenes and polyisopropylbenzenes, are listed in U.S. Pat. No.5,557,024 (Cheng) and include MCM-49, MCM-22, PSH-3, SSZ-25, zeolite X,zeolite Y, zeolite Beta, acid dealuminized mordenite and TEA-mordenite.Transalkylation over a small crystal (<0.5 micron) form of TEA-mordeniteis also disclosed in U.S. Pat. No. 6,984,764.

Where the alkylation step is performed in the liquid phase, it is alsodesirable to conduct the transalkylation step under liquid phaseconditions. However, by operating at relatively low temperatures, liquidphase processes impose increased requirements on the catalyst,particularly in the transalkylation step where the bulky polyalkylatedspecies must be converted to additional monoalkylated product withoutproducing unwanted by-products. This has proven to be a significantproblem in the case of cumene production where existing catalysts haveeither lacked the desired activity or have resulted in the production ofsignificant quantities of by-products such as ethylbenzene andn-propylbenzene.

Although it is suggested in the art that catalysts for conversion offeedstock comprising an alkylatable aromatic compound and an alkylatingagent to alkylaromatic conversion product under at least partial liquidphase conversion conditions are composed of a porous crystallinealuminosilicate and binder in the ratio of crystal/binder of from 1/99,e.g. 5/95, to 100/0, current commercial catalysts, i.e. those found tobe commercially useful, for this process are composed of a porouscrystalline aluminosilicate and binder in the ratio of crystal/binder ofeither 65/35 or 80/20. Finding a commercially acceptable catalyst forsuch processes conducted under at least partial liquid phase conversionconditions which increases monoselectivity, i.e. lower di- or polyalkylproduct make, would allow capacity expansion in existing plants andlower capital expense for grassroots plants as a result of loweraromatic compound/alkylating agent ratios.

U.S. Published Patent Application No. 2011/0178353 to Clark et al.discloses a liquid phase or partial liquid phase alkylation process forproducing alkylaromatics conducted in the presence of a specificcatalyst comprising a porous crystalline material, e.g. a crystallinealuminosilicate, (“crystal”) and binder in the ratio of crystal/binderof from about 20/80 to about 60/40, which yields a unique combination ofactivity and, importantly, monoselectivity. Suitable catalysts disclosedto include the MCM-22 family materials.

The MCM-22 family molecular sieves have been found to be useful in avariety of hydrocarbon conversion processes. Examples of MCM-22 familymolecular sieve are MCM-22, MCM-49, MCM-56, ITQ-1, ITQ-2, PSH-3, SSZ-25,ERB-1, UZM-8, and UZM-8HS. In particular, MCM-56 is a layered oxidematerial, rather than a three dimensionally ordered zeolite, in whicheach layer in MCM-56 is porous and has a framework structure closelyrelated to that of MCM-22 and other MCM-22 family materials.

U.S. Provisional Application No. 61/535,632 to Johnson et al., filedSep. 12, 2011 and incorporated herein by reference in its entirety,discloses an improved method for manufacturing high quality porousseeded-crystalline MCM-56 material by incorporating MCM-56 seed crystalsinto the initial reaction mixture. It also relates to the seeded-MCM-56material manufactured by the improved method, catalyst compositionscomprising same and use thereof in a process for catalytic conversion ofhydrocarbon compounds.

According to the present invention, it has now unexpectedly been foundthat a seeded-MCM-56 crystalline aluminosilicate in combination with abinder in the crystal/binder weight ratio of from above about 20/80 toabout 80/20, preferably from about 40/60 to about 60/40, yields a uniquecombination of activity and, importantly, monoselectivity in liquidphase or partial liquid phase alkylation processes for producingalkylaromatics.

SUMMARY

According to the present invention, there is provided an improvedprocess for conversion of a feedstock comprising an alkylatable aromaticcompound and an alkylating agent to desired alkylaromatic conversionproduct under at least partial liquid phase conversion conditions in thepresence of specific catalyst comprising a porous crystalline material,e.g. a crystalline aluminosilicate, and binder in the ratio ofcrystal/binder of from about 20/80 to about 60/40. According to oneaspect of the invention, there is provided a process for selectivelyproducing a desired monoalkylated aromatic compound comprising the stepof contacting an alkylatable aromatic compound with an alkylating agentin the presence of catalyst composition under at least partial liquidphase conditions, said catalyst composition comprising a porouscrystalline material, e.g. a crystalline aluminosilicate, and binder inthe crystal/binder weight ratio of from about 20/80 to about 60/40.Another aspect of the present invention is an improved alkylationprocess for the selective production of monoalkyl benzene comprising thestep of reacting benzene with an alkylating agent under alkylationconditions in the presence of alkylation catalyst which comprises aporous crystalline material, e.g. a crystalline aluminosilicate, andbinder in the ratio of crystal/binder of from about 20/80 to about60/40.

The catalyst for use in the present process may comprise, for example, acrystalline molecular sieve having the structure of zeolite Beta, or onehaving an X-ray diffraction pattern including d-spacing maxima at12.4±0.25, 6.9±0.15, 3.57±0.07 and 3.42±0.07 Angstroms. Moreparticularly, the catalyst for use herein may comprise a crystallinemolecular sieve having the structure of Beta, an MCM-22 family material,e.g. MCM-22, or a mixture thereof.

In another aspect, the present invention is directed to a process forselective conversion of benzene to ethyl benzene comprising contacting afeedstock containing benzene with ethylene under at least partial liquidphase conversion conditions in the presence of a seeded MCM-56crystal/binder composition having a ratio of crystal/binder of fromabove about 20/80 to about 60/40.

In another aspect, the present invention is directed to a process forselectively alkylating benzene with ethylene to form ethyl benzene,comprising manufacturing synthetic porous crystalline MCM-56 materialcomprising the steps of a) preparing a first reaction mixture containingsources of alkali or alkaline earth metal (M) cation, an oxide of atrivalent element X, an oxide of a tetravalent element Y, and water,said first reaction mixture having a composition in terms of mole ratiosof oxides within the following ranges: YO₂/X₂O₃=5 to 35; H₂O/YO₂=10 to70; OH⁻/YO₂=0.05 to 0.20; M/YO₂=0.05 to 3.0; said first reaction mixturefurther comprising zeolite seed crystals in an amount from greater thanor equal to 0.05 wt. % to less than or equal to 5 wt. %, based on theweight of said first reaction mixture; b) adding directing agent R tothe reaction mixture of step a) to form a second reaction mixture,having said directing agent R in terms of a mole ratio within thefollowing range: R/YO₂=0.08 to 0.3; c) crystallizing said secondreaction mixture of step b) under conditions of temperature of fromabout 90° C. to about 175° C. and a time for less than 90 hours to forma resulting mixture comprising crystals of a seeded MCM-56 material andless than 10 wt. % non-MCM-56 impurity crystals based on the totalweight of said MCM-56 crystals in said second reaction mixture, asidentified by X-ray diffraction; and d) separating and recovering atleast a portion of said crystals of said seeded MCM-56 material fromsaid resulting mixture of step c), wherein said crystals of said seededMCM-56 material have an X-ray diffraction pattern as shown in Table 1below:

TABLE 1 Interplanar d-Spacing (Angstroms) Relative Intensity 12.4 ± 0.2 vs 9.9 ± 0.3 m 6.9 ± 0.1 w 6.4 ± 0.3 w 6.2 ± 0.1 w 3.57 ± 0.07 m-s 3.44± 0.07 vscombining said seeded MCM-56 crystals with a binder in a crystal/binderweight ratio from above about 20/80 to about 80/20 to form a catalystcomposition; and contacting a feedstock containing benzene with ethylenein at least partial liquid phase under catalytic alkylation conditionsincluding a temperature of from about 0° C. to about 500° C., a pressurefrom about 20 to about 25000 kPa-a, a molar ratio of benzene to ethyleneof from about 0.1:1 to about 50:1, and a feed weight hourly spacevelocity (WHSV) based on the ethylene of from about 0.1 to about 500hr⁻¹, with said catalyst composition.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a plot of diisopropylbenzene/isopropylbenzene selectivity(ordinate) versus the percentage of MCM-56 in the 1/20″ quadrulobeextrudate bound with Versal 300 alumina, for non-seeded MCM-56(abscissa), ex-situ seeded MCM-56 and in-situ seeded MCM-56.

FIG. 2 shows a plot of triisopropylbenzene/isopropylbenzene selectivity(ordinate) versus the percentage of MCM-56 in the 1/20″ quadrulobeextrudate bound with Versal 300 alumina (abscissa), for non-seededMCM-56, ex-situ seeded MCM-56 and in-situ seeded MCM-56.

FIG. 3 shows a plot of activity (as a 2nd order rate constant k₂ times1000) (ordinate) versus the percentage of MCM-56 in the 1/20″ quadrulobeextrudate bound with Versal 300 alumina (abscissa), for non-seededMCM-56, ex-situ seeded MCM-56 and in-situ seeded MCM-56.

FIG. 4 shows a plot of diisopropylbenzene/triisopropylbenzeneselectivity (ordinate) versus the percentage of MCM-56 in the 1/20″quadrulobe extrudate bound with Versal 300 alumina (abscissa), fornon-seeded MCM-56, ex-situ seeded MCM-56 and in-situ seeded MCM-56.

FIG. 5 shows a plot of the diethylbenzene/ethylbenzene selectivity(ordinate) versus the ethylene conversion (abscissa) for the processesof Examples 16.1-16.5.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to an improved process for production ofmonoalkylated aromatic compounds, particularly ethylbenzene, cumene andsec-butylbenzene, by the liquid or partial liquid phase alkylation of analkylatable aromatic compound, particularly benzene. More particularly,the present process uses a catalyst composition comprising a porouscrystalline material, e.g. a crystalline aluminosilicate, and binder ata crystal/binder weight ratio of from above about 20/80 to about 80/20,or from above about 20/80 to about 60/40, preferably from about 20/80 toabout 40/60, or even more preferably from about 40/60 to about 60/40.

Methods for producing the catalysts required for use in the presentinvention comprise those taught in the publications listed below andincorporated herein by reference, modified only by adjusting thecompounding or extrusion, for example, of the final catalyst to comprisea crystal/binder ratio of from about 20/80 to about 60/40. This is wellwithin the ability of those skilled in catalyst manufacturing art. Forexample, U.S. Pat. No. 4,954,325 describes crystalline MCM-22 andcatalyst comprising same, U.S. Pat. No. 5,236,575 describes crystallineMCM-49 and catalyst comprising same, and U.S. Pat. Nos. 5,362,697 and5,557,024 describe crystalline MCM-56 and catalyst comprising same. Incompounding or extruding the particular crystalline material with binderto form the catalyst required for use herein, care is taken to do sosuch that the final catalyst product comprises a crystal/binder ratio offrom about 20/80 to about 60/40 or from above about 20/80 to about80/20, preferably from about 40/60 to about 80/20, or even morepreferably from about 40/60 to about 60/40.

The term “ex-situ seeded” as used herein refers to a method forintroducing zeolite seeds into a zeolite synthesis reactor in whichzeolite seeds in their as-synthesized condition are added to thereactor.

The term “in-situ seeded” as used herein refers to a method forintroducing zeolite seeds into a zeolite synthesis reactor in whichresidual zeolite seeds in their as-synthesized condition remain in thereactor from a previous zeolite crystallization.

The term “aromatic” in reference to the alkylatable aromatic compoundswhich may be useful as feedstock herein is to be understood inaccordance with its art-recognized scope. This includes alkylsubstituted and unsubstituted mono- and polynuclear compounds. Compoundsof an aromatic character that possess a heteroatom are also usefulprovided they do not act as catalyst poisons under the reactionconditions selected.

Substituted aromatic compounds that can be alkylated herein must possessat least one hydrogen atom directly bonded to the aromatic nucleus. Thearomatic rings can be substituted with one or more alkyl, aryl, alkaryl,alkoxy, aryloxy, cycloalkyl, halide, and/or other groups that do notinterfere with the alkylation reaction.

Suitable aromatic compounds include benzene, naphthalene, anthracene,naphthacene, perylene, coronene, and phenanthrene, with benzene beingpreferred.

Generally the alkyl groups that can be present as substituents on thearomatic compound contain from 1 to about 22 carbon atoms and usuallyfrom about 1 to 8 carbon atoms, and most usually from about 1 to 4carbon atoms.

Suitable alkyl substituted aromatic compounds include toluene, xylene,isopropylbenzene, n-propylbenzene, alpha-methylnaphthalene,ethylbenzene, mesitylene, durene, cymenes, butylbenzene, pseudocumene,o-diethylbenzene, m-diethylbenzene, p-diethylbenzene, isoamylbenzene,isohexylbenzene, pentaethylbenzene, pentamethylbenzene;1,2,3,4-tetraethylbenzene; 1,2,3,5-tetramethylbenzene;1,2,4-triethylbenzene; 1,2,3-trimethylbenzene, m-butyltoluene;p-butyltoluene; 3,5-diethyltoluene; o-ethyltoluene; p-ethyltoluene;m-propyltoluene; 4-ethyl-m-xylene; dimethylnaphthalenes;ethylnaphthalene; 2,3-dimethylanthracene; 9-ethylanthracene;2-methylanthracene; o-methylanthracene; 9,10-dimethylphenanthrene; and3-methyl-phenanthrene. Higher molecular weight alkylaromatic compoundscan also be used as starting materials and include aromatic organicssuch as are produced by the alkylation of aromatic organics with olefinoligomers. Such products are frequently referred to in the art asalkylate and include hexylbenzene, nonylbenzene, dodecylbenzene,pentadecylbenzene, hexyltoluene, nonyltoluene, dodecyltoluene,pentadecyltoluene, etc. Very often alkylate is obtained as a highboiling fraction in which the alkyl group attached to the aromaticnucleus varies in size from about C₆ to about C₁₂. When cumene orethylbenzene is the desired product, the present process producesacceptably little by-products such as xylenes. The xylenes made in suchinstances may be less than about 500 ppm.

Reformate containing a mixture of benzene, toluene and/or xyleneconstitutes a particularly useful feed for the alkylation process ofthis invention.

The alkylating agents that may be useful in the process of thisinvention generally include any aliphatic or aromatic organic compoundhaving one or more available alkylating aliphatic groups capable ofreaction with the alkylatable aromatic compound, preferably with thealkylating group possessing from 1 to 5 carbon atoms. Examples ofsuitable alkylating agents are olefins such as ethylene, propylene, thebutenes, and the pentenes; alcohols (inclusive of monoalcohols,dialcohols, trialcohols, etc.) such as methanol, ethanol, the propanols,the butanols, and the pentanols; aldehydes such as formaldehyde,acetaldehyde, propionaldehyde, butyraldehyde, and n-valeraldehyde; andalkyl halides such as methyl chloride, ethyl chloride, the propylchlorides, the butyl chlorides, and the pentyl chlorides, and so forth.

Mixtures of light olefins are useful as alkylating agents in thealkylation process of this invention. Accordingly, mixtures of ethylene,propylene, butenes, and/or pentenes which are major constituents of avariety of refinery streams, e.g., fuel gas, gas plant off-gascontaining ethylene, propylene, etc., naphtha cracker off-gas containinglight olefins, refinery FCC propane/propylene streams, etc., are usefulalkylating agents herein. For example, a typical FCC light olefin streampossesses the following composition in Table 3A below:

TABLE 3A Wt. % Mole % Ethane 3.3 5.1 Ethylene 0.7 1.2 Propane 4.5 15.3Propylene 42.5 46.8 Isobutane 12.9 10.3 n-Butane 3.3 2.6 Butenes 22.118.32 Pentanes 0.7 0.4

Reaction products that may be obtained from the process of the presentinvention include ethylbenzene from the reaction of benzene withethylene, cumene from the reaction of benzene with propylene,ethyltoluene from the reaction of toluene with ethylene, cymenes fromthe reaction of toluene with propylene, and sec-butylbenzene from thereaction of benzene and n-butene. Particularly preferred processmechanisms of the invention relate to the production of cumene by thealkylation of benzene with propylene, and production of ethylbenzene bythe alkylation of benzene with ethylene.

The reactants for the present improved process can be in partially orcompletely liquid phase and can be neat, i.e. free from intentionaladmixture or dilution with other material, or they can be brought intocontact with the catalyst composition with the aid of carrier gases ordiluents such as, for example, hydrogen or nitrogen.

The improved alkylation process of this invention may be conducted suchthat the reactants, i.e., the alkylatable aromatic compound and thealkylating agent, are brought into contact with the present catalyst ina suitable reaction zone such as, for example, in a flow reactorcontaining a fixed bed of the catalyst composition, under effectivealkylation conditions. Such conditions include a temperature of fromabout 0° C. to about 500° C., preferably from about 10° C. to about 260°C., a pressure of from about 0.2 to about 25000 kPa-a, preferably fromabout 100 to about 5500 kPa-a, a molar ratio of alkylatable aromaticcompound to alkylating agent of from about 0.1:1 to about 50:1,preferably from about 0.5:1 to about 10:1, and a feed weight hourlyspace velocity (WHSV) based on the alkylating agent of from about 0.1 to500 hr⁻¹, preferably from about 0.5 to about 100 hr⁻¹.

When benzene is alkylated with ethylene to produce ethylbenzene, thealkylation reaction is preferably carried out under at least partiallyliquid phase conditions, that is such that at least part of the benzeneis in the liquid phase during the alkylation reaction. Suitableconditions include a temperature of from about 150° C. to about 300° C.,more preferably from about 170° C. to about 260° C.; a pressure up toabout 20400 kPa-a, more preferably from about 2000 kPa-a to about 5500kPa-a; a weight hourly space velocity (WHSV) based on the ethylenealkylating agent of from about 0.1 to about 20 hr⁻¹, more preferablyfrom about 0.5 to about 6 hr⁻¹; and a ratio of benzene to ethylene inthe alkylation reactor of from about 0.5:1 to about 30:1 molar, morepreferably from about 1:1 to about 10:1 molar.

When benzene is alkylated with propylene to produce cumene, the reactionmay also take place under at least partially liquid phase conditionsincluding a temperature of up to about 250° C., preferably up to about150° C., e.g., from about 10° C. to about 125° C.; a pressure of about25000 kPa-a or less, e.g., from about 100 to about 3000 kPa-a; a weighthourly space velocity (WHSV) based on propylene alkylating agent of fromabout 0.1 hr⁻¹ to about 250 hr⁻¹, preferably from about 1 hr⁻¹ to about50 h⁻¹; and a ratio of benzene to propylene in the alkylation reactor offrom about 0.5:1 to about 30:1 molar, more preferably from about 1:1 toabout 10:1 molar.

When benzene is alkylated with butenes, e.g. n-butene, to producebutylbenzene, e.g. sec-butylbenzene, the reaction may also take placeunder at least partially liquid phase conditions including a temperatureof up to about 250° C., preferably up to about 150° C., e.g., from about10° C. to about 125° C.; a pressure of about 25000 kPa-a or less, e.g.,from about 100 to about 3000 kPa-a; a weight hourly space velocity(WHSV) based on butenes alkylating agent of from about 0.1 hr⁻¹ to about250 hr⁻¹, preferably from about 1 hr⁻¹ to about 50 hr⁻¹; and a ratio ofbenzene to butenes in the alkylation reactor of from about 0.5:1 toabout 30:1 molar, more preferably from about 1:1 to about 10:1 molar.

The crystal portion of the catalyst for use in the present invention maycomprise a crystalline molecular sieve having the structure of zeoliteBeta (described in U.S. Pat. No. 3,308,069) or an MCM-22 familymaterial. The catalyst must include the crystalline molecular sievecombined in a conventional manner with an oxide binder as hereinafterdetailed in the weight ratio of crystal/binder of from about 20/80 toabout 80/20 or from above about 20/80 to about 40/60, preferably fromabout 20/80 to about 40/60, or even more preferably from about 40/60 toabout 60/40.

For certain applications of the catalyst, the average particle size ofthe crystalline molecular sieve component may be from about 0.05 toabout 200 microns, for example, from 20 to about 200 micron.

The term “MCM-22 family material” (or “material of the MCM-22 family” or“molecular sieve of the MCM-22 family”), as used herein, includes:

-   (i) molecular sieves made from a common first degree crystalline    building block “unit cell having the MWW framework topology”. A unit    cell is a spatial arrangement of atoms which is tiled in    three-dimensional space to describe the crystal as described in the    “Atlas of Zeolite Framework Types”, Fifth edition, 2001, the entire    content of which is incorporated as reference;-   (ii) molecular sieves made from a common second degree building    block, a 2-dimensional tiling of such MWW framework type unit cells,    forming a “monolayer of one unit cell thickness”, preferably one    c-unit cell thickness;-   (iii) molecular sieves made from common second degree building    blocks, “layers of one or more than one unit cell thickness”,    wherein the layer of more than one unit cell thickness is made from    stacking, packing, or binding at least two monolayers of one unit    cell thick of unit cells having the MWW framework topology. The    stacking of such second degree building blocks can be in a regular    fashion, an irregular fashion, a random fashion, or any combination    thereof; or-   (iv) molecular sieves made by any regular or random 2-dimensional or    3-dimensional combination of unit cells having the MWW framework    topology.

The MCM-22 family materials are characterized by having an X-raydiffraction pattern including d-spacing maxima at 12.4±0.25, 3.57±0.07and 3.42±0.07 Angstroms (either calcined or as-synthesized). The MCM-22family materials may also be characterized by having an X-raydiffraction pattern including d-spacing maxima at 12.4±0.25, 6.9±0.15,3.57±0.07 and 3.42±0.07 Angstroms (either calcined or as-synthesized).The X-ray diffraction data used to characterize the molecular sieve areobtained by standard techniques using the K-alpha doublet of copper asthe incident radiation and a diffractometer equipped with ascintillation counter and associated computer as the collection system.Materials belong to the MCM-22 family include MCM-22 (described in U.S.Pat. No. 4,954,325), PSH-3 (described in U.S. Pat. No. 4,439,409),SSZ-25 (described in U.S. Pat. No. 4,826,667), ERB-1 (described inEuropean Patent No. 0293032), ITQ-1 (described in U.S. Pat. No.6,077,498), ITQ-2 (described in International Patent Publication No.WO97/17290), ITQ-30 (described in International Patent Publication No.WO2005118476), MCM-36 (described in U.S. Pat. No. 5,250,277), MCM-49(described in U.S. Pat. No. 5,236,575), MCM-56 (described in U.S. Pat.No. 5,362,697), and UZM-8 (described in U.S. Pat. No. 6,756,030). Theentire contents of the patents are incorporated herein by reference.

It is to be appreciated the MCM-22 family molecular sieves describedabove are distinguished from conventional large pore zeolite alkylationcatalysts, such as mordenite, in that the MCM-22 materials have 12-ringsurface pockets which do not communicate with the 10-ring internal poresystem of the molecular sieve.

The zeolitic materials designated by the IZA-SC as being of the MWWtopology are multi-layered materials which have two pore systems arisingfrom the presence of both 10 and 12 membered rings. The Atlas of ZeoliteFramework Types classes five differently named materials as having thissame topology: MCM-22, ERB-1, ITQ-1, PSH-3, and SSZ-25.

The MCM-22 family molecular sieves have been found to be useful in avariety of hydrocarbon conversion processes. Examples of MCM-22 familymolecular sieve are MCM-22, MCM-49, MCM-56, ITQ-1, PSH-3, SSZ-25, andERB-1. Such molecular sieves are useful for alkylation of aromaticcompounds. For example, U.S. Pat. No. 6,936,744 discloses a process forproducing a monoalkylated aromatic compound, particularly cumene,comprising the step of contacting a polyalkylated aromatic compound withan alkylatable aromatic compound under at least partial liquid phaseconditions and in the presence of a transalkylation catalyst to producethe monoalkylated aromatic compound, wherein the transalkylationcatalyst comprises a mixture of at least two different crystallinemolecular sieves, wherein each of the molecular sieves is selected fromzeolite beta, zeolite Y, mordenite and a material having an X-raydiffraction pattern including d-spacing maxima at 12.4±0.25, 6.9±0.15,3.57±0.07 and 3.42±0.07 Angstroms.

In particular, the molecular sieve employed in the present alkylationprocess comprises MCM-56 crystals produced by a process in which thesynthesis mixture comprises seeds of zeolite crystals, especially MCM-56crystals. A suitable process is disclosed in U.S. ProvisionalApplication No. 61/535,632 to Johnson et al, filed Sep. 16, 2011 andincorporated herein by reference in its entirety. The crystalsso-manufactured are characterized herein as seeded MCM-56 crystals.

The seeded MCM-56 crystals are characterized by the X-ray diffractionpattern as disclosed in U.S. Pat. Nos. 5,362,697 and 5,827,491, eachpatent incorporated herein by reference.

The X-ray diffraction pattern disclosed in U.S. Pat. Nos. 5,362,697 and5,827,491 is shown below in Table 1 (as-synthesized) and Table 2(as-calcined). In Tables 1 and 2, the intensities are defined relativeto the d-spacing line at 12.4 Angstroms.

TABLE 1 Interplanar d-Spacing (Angstroms) Relative Intensity 12.4 ± 0.2 vs 9.9 ± 0.3 m 6.9 ± 0.1 w 6.4 ± 0.3 w 6.2 ± 0.1 w 3.57 ± 0.07 m-s 3.44± 0.07 vs

TABLE 2 Interplanar d-Spacing (Angstroms) Relative Intensity 12.4 ± 0.2 vs 9.9 ± 0.3 m 6.9 ± 0.1 w 6.2 ± 0.1 w 3.55 ± 0.07 m-s 3.42 ± 0.07 vs

The above X-ray diffraction data were collected with a Scintagdiffraction system, equipped with a germanium solid state detector,using copper K-alpha radiation. The diffraction data were recorded bystep-scanning at 0.02 degrees of two-theta, where theta is the Braggangle, and a counting time of 10 seconds for each step. The interplanarspacings, d-spacings, were calculated in Angstrom units (A), and therelative intensities of the lines, I/I_(o) is one-hundredth of theintensity of the strongest line, above background, were derived with theuse of a profile fitting routine (or second derivative algorithm). Theintensities are uncorrected for Lorentz and polarization effects. Therelative intensities are given in terms of the symbols vs=very strong(60-100), s=strong (40-60), m=medium (20-40) and w=weak (0-20). Itshould be understood that diffraction data listed for this sample assingle lines may consist of multiple overlapping lines which undercertain conditions, such as differences in crystallographic changes, mayappear as resolved or partially resolved lines. Typically,crystallographic changes can include minor changes in unit cellparameters and/or a change in crystal symmetry, without a change in thestructure. These minor effects, including changes in relativeintensities, can also occur as a result of differences in cationcontent, framework composition, nature and degree of pore filling, andthermal and/or hydrothermal history.

The method for producing seeded MCM-56 crystals comprises the steps of:

a) preparing a first reaction mixture containing sources of alkali oralkaline earth metal (M), e.g., sodium or potassium, cation, an oxide ofa trivalent element X, e.g., aluminum, an oxide of a tetravalent elementY, e.g., silicon, preferably, containing at least 30 wt. % of solid YO₂,and water, said first reaction mixture having a composition in terms ofmole ratios of oxides, preferably, selected within the following rangesin Table 3B below:

TABLE 3B YO₂/X₂O₃ = 5 to 35, e.g., 15 to 20; H₂O/YO₂ = 10 to 70, e.g.,15 to 20; OH⁻/YO₂ = 0.05 to 0.20, e.g., 0.1 to 0.15; M/YO₂ = 0.05 to3.0, e.g., 0.11 to 0.15;said first reaction mixture further comprising zeolite seed crystals,preferably, MCM-56 seed crystals, in an amount from greater than orequal to 0.05 wt. %, or greater than or equal to 0.10 wt. %, or greaterthan or equal to 0.50 wt. %, or greater than or equal to 1.0 wt. %, toless than or equal to 5 wt. %, e.g., greater than or equal to 1 to lessthan or equal to 3 wt. %, based on the weight of the first reactionmixture;

b) adding directing agent R, e.g., preferably, hexamethyleneimine (HMI),to the reaction mixture of step a) to form a second reaction mixturehaving said directing agent R in terms of a mole ratio within thefollowing range: R/YO₂=0.08 to 0.3, e.g., 0.1 to 0.2;

c) crystallizing the second reaction mixture of step b) under conditionsof a temperature of from about 90° C. to about 175° C., preferably, fromabout 90° C. to less than 160° C., e.g., from about 125° C. to about175° C., and a time for less than 90 hours, preferably, for less than 40hours, e.g., from about 20 to about 75 hours, at a stir rate of fromabout 40 to about 250 rpm, preferably, from about 40 to about 100 rpm,to form a resulting mixture comprising crystals of said MCM-56 materialand less than or equal to 10 wt. %, e.g., less than or equal to about 5wt. %, of non-MCM-56 impurity crystals, based on the total weight ofsaid MCM-56 crystals in said second reaction mixture, as identified byX-ray diffraction, such as, for example, crystalline MCM-22 familymaterials (defined below), such as MCM-49 material, or ferrierite,kenyaite or mixtures thereof; and

d) separating and recovering at least a portion of crystals of saidMCM-56 material from the resulting mixture of step c) to formas-synthesized MCM-56 material wherein said crystals of as-synthesizedMCM-56 material is characterized by the X-ray diffraction pattern shownin Table 1 above.

The second reaction mixture of step b) has a solids content of rangefrom at least 12 wt. %, or at least 15 wt. %, or at least 18 wt. %, orat least 20 wt. %, or at least 30 wt. % up to less than 40 wt. %, orless than 50 wt. %, or less than 60 wt. %., based on the weight of thesecond reaction mixture. Preferably, the solids content of the secondreaction mixture of step b) is less than 30 wt. %, based on the weightof the second reaction mixture.

In order to achieve the required first reaction mixture composition forthis improved method, some selective critical changes have to be made tothe method for making MCM-56 material as compared to the currentpractice. For example, the addition of caustic NaOH is eliminated,except as a component of, for example, sodium aluminate. Also, theorganic directing agent is not added to the first reaction mixtureduring its formation, but a controlled amount of organic directing agentreduced to nearly stoichiometric amounts is only added to the fullyformed first reaction mixture to form the second reaction mixture.Further, zeolite seeds crystals, preferably, zeolite seed crystals ofMCM-22 family material, more preferably, zeolite seed crystals ofMCM-56, are added to the first reaction mixture based on its totalweight such that the amount of seed crystals is from greater than orequal to 0.05 wt. %, or greater than or equal to 0.10 wt. %, or greaterthan or equal to 0.50 wt. %, or greater than or equal to 1.0 wt. %, toless than or equal to 5 wt. %, e.g., from greater than or equal to 1 toless than or equal to 3 wt. %, of the first reaction mixture.Surprisingly, adding MCM-56 seed crystals to the first reaction mixturerequired for this improved method does not accelerate the formation ofimpurities as would normally be expected in such a crystallizationprocedure.

The improved method of this invention beneficially stabilizes andextends the crystallization window in step c) of the method to avoidimpurity, e.g., MCM-49 material, formation; reduces organic loading inthe crystallization step c) lowering cost, especially important incommercial MCM-56 manufacturing; and accelerates the crystallizationrate in step c) to greatly improve throughput. Further, the intentionaladdition of the preferred MCM-56 seed crystals swamps out normallyexpected effects of acceleration of crystallization of impurities causedby residual particles in the crystallizer. This is especially importantin commercial manufacturing. In the improved method, seeding did notaccelerate the introduction of impurities.

In the present improved method, the source of YO₂ must comprise solidYO₂, for example at least about 30 wt. % solid YO₂. When YO₂ is silica,the use of a silica source containing at least about 30 wt. % solidsilica, e.g., Ultrasil, now known as Sipernat® (a precipitated, spraydried silica containing about 90 wt. % silica) or HiSil™ (a precipitatedhydrated silica containing about 87 wt. % silica, about 6 wt. % free H₂Oand about 4.5 wt. % bound H₂O of hydration and having a particle size ofabout 0.02 micron) favors crystalline MCM-56 formation from the abovesecond reaction mixture under the synthesis conditions required.Preferably, therefore, the YO₂, e.g., silica, source contains at leastabout 30 wt. % solid YO₂, e.g., silica, and more preferably at leastabout 40 wt. % solid YO₂, e.g., silica.

Organic directing agent R may be selected from the group consisting ofcycloalkylamine, azacycloalkane, diazacycloalkane, and combinationsthereof, alkyl comprising from 5 to 8 carbon atoms. Non-limitingexamples of R include cyclopentylamine, cyclohexylamine,cycloheptylamine, hexamethyleneimine (HMI), heptamethyleneimine,homopiperazine, and combinations thereof.

It is noted that the reaction mixture components can be supplied by morethan one source. The reaction mixture can be prepared either batchwiseor continuously. Step c) crystallization of the second reaction mixturein the present method is preferably carried out under stirred conditionsin a suitable reactor vessel, such as for example, polypropylenecontainers or Teflon lined or stainless steel autoclaves. However, it iswithin the scope of this invention for crystallization to occur understatic conditions.

The useful ranges of conditions for crystallization in this method are atemperature from about 90° C. to about 175° C., preferably, from about90° C. to less than 160° C., e.g., from about 125° C. to about 175° C.,and a time for less than 90 hours, preferably, for less than 40 hours,e.g., from about 20 to about 75 hours, preferably, at a stir rate offrom about 40 to about 250 rpm, more preferably, from about 40 to about100 rpm, to form a resulting mixture comprising high quality crystals ofMCM-56 material and less than or equal to 10 wt. % non-MCM-56 impuritycrystals, based on the total weight of said MCM-56 crystals recoveredfrom the reaction mixture, as identified by X-ray diffraction.Thereafter, the crystals of as-synthesized MCM-56 material are separatedfrom the resulting liquid mixture and recovered in step d).

Another embodiment of the improved method comprises aging the secondreaction mixture of step b) prior to crystallizing step c) for fromabout 0.5 to about 48 hours, for example from about 0.5 to about 24hours, at a temperature of from about 25 to about 75° C. Preferably, thesecond reaction mixture was agitated with stirring at, for example 50rpm, for less than 48 hours at ambient temperature.

Catalyst comprising the seeded MCM-56 material manufactured hereby maybe used to effect conversion in chemical reactions, and is particularlyuseful in a process for selectively producing a desired monoalkylatedaromatic compound comprising the step of contacting an alkylatablearomatic compound with an alkylating agent in the presence of thecatalyst under at least partial liquid phase conditions. Another aspectof the present invention, therefore, is an improved alkylation catalystcomprising the high quality seeded MCM-56 manufactured by the presentimproved method for use in a process for the selective production of aproduct comprising monoalkylated benzene, the process comprising thestep of reacting benzene with an alkylating agent, such as ethylene orpropylene, under alkylation conditions in the presence of saidalkylation catalyst to form said product. Using the present catalyst asan alkylation catalyst to effect alkylation of an alkylatable aromaticcompound, the alkylating agent may include an alkylating aliphatic grouphaving 1 to 5 carbon atoms. The alkylating agent may be, for example,ethylene or propylene and the alkylatable aromatic compound in such aninstance may suitably be benzene.

In one or more embodiments of the process for the selective productionof monoalkylated benzene, the product may further comprise formation ofdialkylated benzene and trialkylated benzene may occur. In such case,the weight ratio of the trialkylated benzene to dialkylated benzene isin the range from 0.02 to 0.16, or from 0.4 to 0.16, or from 0.08 to0.12.

The MCM-56 manufactured hereby may be used as a catalyst component toeffect hydrocarbon compound conversion, and is particularly useful ascatalyst in a process for selectively producing ethylbenzene or cumene,the process comprising the step of contacting benzene with ethylene orpropylene under at suitable alkylation conditions, such as at leastpartial liquid phase conditions.

The catalyst for use in the alkylation process of the present inventionwill include an inorganic oxide material matrix or binder. Such matrixor binder materials include synthetic or naturally occurring substancesas well as inorganic materials such as clay, silica and/or metal oxides.The latter may be either naturally occurring or in the form ofgelatinous precipitates or gels including mixtures of silica and metaloxides. Naturally occurring clays which can be composited with theinorganic oxide material include those of the montmorillonite and kaolinfamilies, which families include the subbentonites and the kaolinscommonly known as Dixie, McNamee, Georgia and Florida clays or others inwhich the main mineral constituent is halloysite, kaolinite, dickite,nacrite or anauxite. Such clays can be used in the raw state asoriginally mined or initially subjected to calcination, acid treatmentor chemical modification.

Specific useful catalyst matrix or binder materials employed hereininclude silica, alumina, zirconia, titania, silica-alumina,silica-magnesia, silica-zirconia, silica-thoria, silica-beryllia,silica-titania as well as ternary compositions such assilica-alumina-thoria, silica-alumina-zirconia, silica-alumina-magnesiaand silica-magnesia-zirconia. The matrix can be in the form of a cogel.A mixture of these components could also be used.

In the present process of making ethylbenzene from benzene and ethylene,the relative proportions of the seeded MCM-56 crystals and binder ormatrix may vary narrowly with the ratio of crystal/binder of from aboveabout 20/80 to about 80/20, preferably from about 40/60 to about 80/20,or even from about 40/60 to 60/40.

In the process of the present invention, the alkylation reactor effluentmay contain excess aromatic feed, monoalkylated product, polyalkylatedproducts, and various impurities. The aromatic feed is recovered bydistillation and recycled to the alkylation reactor. Usually a smallbleed is taken from the recycle stream to eliminate unreactiveimpurities from the loop. The bottoms from the distillation may befurther distilled to separate monoalkylated product from polyalkylatedproducts and other heavies.

The polyalkylated products separated from the alkylation reactoreffluent may be reacted with additional aromatic feed in atransalkylation reactor, separate from the alkylation reactor, over asuitable transalkylation catalyst. The transalkylation catalyst maycomprise one or a mixture of crystalline molecular sieves having thestructure of zeolite Beta, zeolite Y, mordenite or an MCM-22 familymaterial having an X-ray diffraction pattern including d-spacing maximaat 12.4±0.25, 6.9±0.15, 3.57±0.07 and 3.42±0.07 Angstroms.

The X-ray diffraction data used to characterize said above catalyststructures are obtained by standard techniques using the K-alpha doubletof copper as the incident radiation and a diffractometer equipped with ascintillation counter and associated computer as the collection system.Materials having the above X-ray diffraction lines include, for example,MCM-22 (described in U.S. Pat. No. 4,954,325), PSH-3 (described in U.S.Pat. No. 4,439,409), SSZ-25 (described in U.S. Pat. No. 4,826,667),ERB-1 (described in European Patent No. 0293032), ITQ-1 (described inU.S. Pat. No. 6,077,498), ITQ-2 (described in U.S. Pat. No. 6,231,751),ITQ-30 (described in WO 2005-118476), MCM-36 (described in U.S. Pat. No.5,250,277), MCM-49 (described in U.S. Pat. No. 5,236,575) and MCM-56(described in U.S. Pat. No. 5,362,697), with MCM-22 being particularlypreferred.

Zeolite Beta is disclosed in U.S. Pat. No. 3,308,069. Zeolite Y andmordenite occur naturally but may also be used in one of their syntheticforms, such as Ultrastable Y (USY), which is disclosed in U.S. Pat. No.3,449,070, Rare earth exchanged Y (REY), which is disclosed in U.S. Pat.No. 4,415,438, and TEA-mordenite (i.e., synthetic mordenite preparedfrom a reaction mixture comprising a tetraethylammonium directingagent), which is disclosed in U.S. Pat. Nos. 3,766,093 and 3,894,104.However, in the case of TEA-mordenite for use in the transalkylationcatalyst, the particular synthesis regimes described in the patentsnoted lead to the production of a mordenite product composed ofpredominantly large crystals with a size greater than 1 micron andtypically around 5 to 10 micron. It has been found that controlling thesynthesis so that the resultant TEA-mordenite has an average crystalsize of less than 0.5 micron results in a transalkylation catalyst withmaterially enhanced activity for liquid phase aromatics transalkylation.

The small crystal TEA-mordenite desired for transalkylation can beproduced by crystallization from a synthesis mixture having a molarcomposition within the following ranges in Table 3C below:

TABLE 3C Useful Preferred R/R⁺Na⁺ = >0.4  0.45-0.7 OH⁻/SiO₂ = <0.220.05-0.2 Si/Al₂ = >30-90  35-50 H₂O/OH =  50-70  50-60

The crystallization of small crystal TEA-mordenite from this synthesismixture is conducted at a temperature of 90 to 200° C., for a time of 6to 180 hours.

EXAMPLES

Non-limiting examples of the invention involving an improved alkylationmechanism are described with reference to the following experiments. Inthese experiments, catalyst reactivity was measured by the followingprocedure.

Equipment

A 300 ml Parr batch reaction vessel equipped with a stir rod and staticcatalyst basket was used for the activity and selectivity measurements.The reaction vessel was fitted with two removable vessels for theintroduction of benzene and propylene respectively.

Feed Pretreatment

Benzene

Benzene was obtained from a commercial source. The benzene was passedthrough a pretreatment vessel (2 L Hoke vessel) containing 500 cc. ofmolecular sieve 13×, followed by 500 cc. of molecular sieve 5A, then1000 cc. of Selexsorb CD, then 500 cc. of 80 wt. % MCM-49 and 20 wt. %Al₂O₃. All feed pretreatment materials were dried in a 260° C. oven for12 hours before using.

Propylene

Propylene was obtained from a commercial specialty gases source and waspolymer grade. The propylene was passed through a 300 ml vesselcontaining pretreatment materials in the following order:

a. 150 ml molecular sieve 5A

b. 150 ml Selexsorb CD

Both guard-bed materials were dried in a 260° C. oven for 12 hoursbefore using.

Nitrogen

Nitrogen was ultra high purity grade and obtained from a commercialspecialty gases source. The nitrogen was passed through a 300 ml vesselcontaining pretreatment materials in the following order:

a. 150 ml molecular sieve 5A

b. 150 ml Selexsorb CD

Both guard-bed materials were dried in a 260° C. oven for 12 hoursbefore using.

Catalyst Preparation and Loading

A 2 gram sample of catalyst was dried in an oven in air at 260° C. for 2hours. The catalyst was removed from the oven and immediately 1 gram ofcatalyst was weighed. Quartz chips were used to line the bottom of abasket followed by loading of 0.5 or 1.0 gram of catalyst into thebasket on top of the first layer of quartz. Quartz chips were thenplaced on top of the catalyst. The basket containing the catalyst andquartz chips was placed in an oven at 260° C. overnight in air for about16 hours.

The basket containing the catalyst and quartz chips was removed from theoven and immediately placed in the reactor and the reactor wasimmediately assembled.

Test Sequence

The reactor temperature was set to 170° C. and purged with 100 sccm(standard cubic centimeter) of the ultra high purity nitrogen for 2hours. After nitrogen purged the reactor for 2 hours, the reactortemperature was reduced to 130° C., the nitrogen purge was discontinuedand the reactor vent closed. A 156.1 gram quantity of benzene was loadedinto a 300 ml transfer vessel, performed in a closed system. The benzenevessel was pressurized to 2169 kPa-a (300 psig) with the ultra highpurity nitrogen and the benzene was transferred into the reactor. Theagitator speed was set to 500 rpm and the reactor was allowed toequilibrate for 1 hour. A 75 ml Hoke transfer vessel was then filledwith 28.1 grams of liquid propylene and connected to the reactor vessel,and then connected with 2169 kPa-a (300 psig) ultra high puritynitrogen. After the one-hour benzene stir time had elapsed, thepropylene was transferred from the Hoke vessel to the reactor. The 2169kPa-a (300 psig) nitrogen source was maintained connected to thepropylene vessel and open to the reactor during the entire run tomaintain constant reaction pressure during the test. Liquid productsamples were taken at 30, 60, 90, 120, and 180 minutes after addition ofthe propylene.

In the Examples below, selectivity is the weight ratio of recoveredproduct diisopropylbenzene to recovered product isopropylbenzene(DIPB/IPB) after propylene conversion reached 99+%. The activity of allexamples is determined by calculating the 2nd order rate constant for abatch reactor using mathematical techniques known to those skilled inthe art.

Example 1

Sixteen parts water and 1 part 45% sodium aluminate solution (22% Al₂O₃,19.5% Na₂O), were charged to an autoclave reactor. The solution wasagitated at 60 rpm for 1 to 24 hours at ambient temperature. Then 3.14parts SiO₂ (Ultrasil-VN3PM-Modified, now known as Sipernat 320C andobtainable from Evoniks, formerly Degussa) and 0.02 part MCM-56 seeds(drycake) were added to form the first reaction mixture. The reactor wassealed and pressure tested. Then 0.53 part hexamethyleneimine (HMI as100% organic) was charged to the reactor to form the second reactionmixture. The second reaction mixture was agitated at 50 rpm for lessthan 48 hours at ambient temperature. The reactor was then heated to151° C. at 50 rpm and the contents were allowed to crystallize for 28hours forming a resulting mixture. The resulting mixture comprisedMCM-56 and less than 10 wt. % impurity as confirmed by X-raydiffraction. The reactor was cooled to 127° C. and the organic removedvia the HMI/water azeotrope, i.e., “flashed”, into a collection vessel.The flashed solvent (“condensate”) was collected for recycle bycombining with additional fresh HMI for subsequent batches. The reactorwas cooled and the product discharged. The extent of crystallization wasconfirmed by BET surface area. Formulation particulars and results forthis Example 1 are reported in Tables 4 and 5 below.

Example 1.1

Sixteen parts water, 1 part 45% sodium aluminate solution (22% Al₂O₃,19.5% Na₂O), 3.13 parts SiO₂ (Sipernat 320C), 0.02 part MCM-56 seeds,and 0.53 part hexamethyleneimine (HMI as 100% organic) were charged toan autoclave reactor. The reactor was sealed and pressure tested. Theresulting solution was agitated at 250 rpm for less than 48 hours atambient temperature. The autoclave was then heated to 151° C. at 250 rpmand the contents were allowed to react for 72 hours. At that time it wasconfirmed by X-ray diffraction that the product was amorphous. Thereactor was cooled to 127° C. and the organic removed via the HMI/waterazeotrope, i.e., “flashed”, into a collection vessel. The reactor wascooled and the product discharged. The lack of crystallization wasconfirmed by

BET surface area. Formulation particulars and results for this Example1.1 are reported in Tables 4 and 5 below.

Example 1.2

Sixteen parts water, 1 part 45% sodium aluminate solution (22% Al₂O₃,19.5% m Na₂O), 3.14 parts SiO₂ (Sipernat 320C) and 0.02 part MCM-56seeds (drycake) were charged to an autoclave reactor to form the firstreaction mixture, and then 0.53 part hexamethyleneimine (HMI as 100%organic) was charged to the reactor to form the second reaction mixture.The reactor was sealed and pressure tested. The second reaction mixturewas agitated at 250 rpm for less than 48 hours at ambient temperature.The reactor was heated to 151° C. at 250 rpm and the contents wereallowed to crystallize for 72 hours forming a resulting mixture. Theresulting mixture comprised MCM-56 and less than 10 wt. % impurity asconfirmed by X-ray diffraction. The reactor was cooled to 127° C. andthe organic removed via the HMI/water azeotrope, i.e., “flashed”, into acollection vessel. The reactor was cooled and the product discharged.For some crystals, the extent of crystallization was confirmed by BETsurface area. Formulation particulars and results for this Example 1.2are reported in Tables 4 and 5 below.

Example 2

Sixteen parts water and 1 part 45% sodium aluminate solution (22% Al₂O₃,19.5% Na₂O), were charged to an autoclave reactor. The solution wasagitated at 60 rpm for 1 to 24 hours at ambient temperature. Then 3.14parts SiO₂ (Sipernat 320C) and 0.02 part MCM-56 seeds (drycake) wereadded to form the first reaction mixture. The reactor was sealed andpressure tested. Then 0.53 part hexamethyleneimine (HMI as 100% organic)was charged to the reactor to form the second reaction mixture. Thesecond reaction mixture was agitated at 50 rpm for less than 48 hours atambient temperature. The reactor was sealed, heated to 141.5° C. at 50rpm and the contents were allowed to crystallize for 36 hours forming aresulting mixture. The resulting mixture comprised MCM-56 and less than10 wt. % impurity as confirmed by X-ray diffraction. The reactor wascooled to 127° C. and the organic removed via the HMI/water azeotrope,i.e., “flashed”, into a collection vessel. The flashed solvent(“condensate”) was collected for recycle by combining with additionalfresh HMI for subsequent batches. The reactor was cooled and the productdischarged. The extent of crystallization was confirmed by BET surfacearea. Formulation particulars and results for this Example 2 arereported in Tables 4 and 5 below.

Example 3

To approximately 0.02 part MCM-56 seeds in the as-synthesized condition,left in the reactor from a previous MCM-56 crystallization, was added0.72 part water and 1 part 5% USALCO, a sodium aluminate solution(as-received solution diluted with additional water from the original22% Al₂O₃ and 19.5% Na₂O to be 2.9% Al₂O₃ and 1.8% Na₂O) in an autoclavereactor. The solution was agitated at 60 rpm for 1 to 24 hours atambient temperature. Then 0.31 part SiO₂ (Sipernat 320C) was added toform the first reaction mixture. The reactor was sealed and pressuretested. Then 0.053 part hexamethyleneimine (HMI as 100% organic) wascharged to the reactor to form the second reaction mixture. The secondreaction mixture was agitated at 60 rpm for less than 48 hours atambient temperature. The reactor was sealed, heated to 148.5° C. at 60rpm and the contents were allowed to crystallize for 36 hours forming aresulting mixture. The resulting mixture comprised MCM-56 and less than10 wt. % impurity as confirmed by X-ray diffraction. The reactor wascooled to 127° C. and the organic removed via the HMI/water azeotrope,i.e., “flashed”, into a collection vessel. The flashed solvent(“condensate”) was collected for recycle by combining with additionalfresh HMI for subsequent batches. The reactor was cooled and the productdischarged. The extent of crystallization was confirmed by BET surfacearea. Formulation particulars and results for this Example 3 arereported in Tables 4 and 5 below.

Example 3.1

To 0.702 parts water was added 1 part 5% sodium aluminate obtainablefrom USALCO (as-received solution diluted with additional water from theoriginal 22% Al₂O₃ and 19.5% Na₂O to be 2.9% Al₂O₃ and 1.8% Na₂O) in anautoclave reactor. The solution was agitated at 60 rpm for 1 to 24 hoursat ambient temperature. Then 0.31 part SiO₂ (Sipernat 320C) was added toform a first reaction mixture, but without seed crystals. The reactorwas sealed and pressure tested. Then 0.053 part hexamethyleneimine (HMIas 100% organic) was charged to the reactor to form the second reactionmixture. The second reaction mixture was agitated at 60 rpm for lessthan 48 hours at ambient temperature. The reactor was sealed, heated to148.5° C. at 60 rpm and the contents were allowed to crystallize for 61hours. MCM-56 was confirmed by X-ray diffraction. The reactor was cooledto 127° C. and the organic removed via the HMI/water azeotrope, i.e.,“flashed”, into a collection vessel. The flashed solvent (“condensate”)was collected for recycle by combining with additional fresh HMI forsubsequent batches. The reactor was cooled and the product discharged.The extent of crystallization was confirmed by BET surface area.Formulation particulars and results for this Example 3.1 are reported inTables 4 and 5 below.

Example 4

To approximately 0.02 part MCM-56 seeds in the as-synthesized condition,left in the reactor from previous MCM-56 crystallization, was added 0.72part water and 1 part 5% USALCO (as-received solution diluted withadditional water from the original 22% Al₂O₃ and 19.5% Na₂O to be 2.9%Al₂O₃ and 1.8% Na₂O) in an autoclave reactor. The solution was agitatedat 60 rpm for 1 to 24 hours at ambient temperature. Then 0.32 part SiO₂(Sipernat 320C) was added to form the first reaction mixture. Thereactor was sealed and pressure tested. Then 0.17 parthexamethyleneimine (HMI as 100% organic) was charged to the reactor toform the second reaction mixture. The second reaction mixture wasagitated at 60 rpm for less than 48 hours at ambient temperature. Thereactor was sealed, heated to 141.5° C. at 60 rpm and the contents wereallowed to crystallize for 33 hours, at which time crystallization wasstopped due to the resulting mixture not progressing to fullcrystallization. The reactor was cooled to 127° C. and the organicremoved via the HMI/water azeotrope, i.e., “flashed”, into a collectionvessel. The reactor was cooled and the product discharged. The lack ofcrystallization was confirmed by BET surface area. Formulationparticulars and results for this Example 4 are reported in Tables 4 and5 below.

Example 4.1

One part 5% USALCO (as-received solution diluted with additional waterfrom the original 22% Al₂O₃ and 19.5% Na₂O to be 2.9% Al₂O₃ and 1.8%Na₂O) and 0.72 part water were charged to an autoclave reactor. Then0.32 part SiO₂ (Sipernat 320C) was added. The reactor was sealed andpressure tested. The solution was agitated at 60 rpm for 1 to 24 hoursat ambient temperature. Then 0.17 part hexamethyleneimine (HMI as 100%organic) was charged to the reactor to form the second reaction mixture.The second reaction mixture was agitated at 60 rpm for less than 48hours at ambient temperature. The reactor was sealed, heated to 141.5°C. at 60 rpm and the contents were allowed to crystallize for 69 hours.At that time crystallization to MCM-56 was confirmed by X-raydiffraction, the reactor was cooled to 127° C. and the organic removedvia the HMI/water azeotrope, i.e., “flashed”, into a collection vessel.The reactor was cooled and the product discharged. The extent ofcrystallization was confirmed by BET surface area. Formulationparticulars and results for this Example 4.1 are reported in Tables 4and 5 below.

Example 5

Sixteen parts water and 1 part 45% sodium aluminate solution (22% Al₂O₃,19.5% Na₂O), were charged to an autoclave reactor. The solution wasagitated between 60 and 250 rpm for 1 to 24 hours at ambienttemperature. Then 3.43 parts SiO₂ (Sipernat 320C) was added to thereactor. The reactor was sealed and pressure tested. Then 0.53 partshexamethyleneimine (HMI as 100% organic) were charged to the reactor toform the second reaction mixture. The second reaction mixture wasagitated at 60 rpm for less than 48 hours at ambient temperature. Thereactor was sealed, heated to 148.5° C. at 60 rpm and the contents wereallowed to crystallize for 56 hours. At that time crystallization toMCM-56 was confirmed by X-ray diffraction, the reactor was cooled to127° C. and the organic removed via the HMI/water azeotrope, i.e.,“flashed”, into a collection vessel. The reactor was cooled and theproduct discharged. The extent of crystallization was confirmed by BETsurface area. Formulation particulars and results for this Example 5 arereported in Tables 4 and 5 below.

TABLE 4 SiO₂/ OH/ H₂O/ R/ M/ Example Al₂O₃ SiO₂ SiO₂ SiO₂ SiO₂ Seeds* 119 0.12 19 0.11 0.14 1.0 1.1 19 0.12 19 0.11 0.14 0.0 1.2 19 0.12 190.11 0.14 1.0 2 19 0.12 19 0.11 0.14 1.0 3 17 0.11 18 0.11 0.13 1.0 3.117 0.11 18 0.11 0.13 0.0 4 17 0.11 19 0.34 0.12 1.0 4.1 17 0.11 19 0.360.12 0.0 5 21 0.11 17 0.10 0.13 0.0 *Seeds in weight percent based onthe weight of the crystals recovered from the reaction mixture.

TABLE 5 Example Temperature, ° C. Stir Rate, rpm Time** 1 151 50 28 1.1151 250 72 (amorphous) 1.2 151 250 72 2 141.5 50 36 3 148.5 60 36 3.1148.5 60 61 4 141.5 60 33 (not fully crystallized) 4.1 141.5 60 69 (veryslow) 5 148.5 60 56 **Time in hours until crystallization is complete ornot progressing.

It is observed from Example 1.1 that the first reaction mixture withoutthe required MCM-56 seed crystals to form a second reaction mixture,even at higher sheer and the same temperature, did not crystallize inover 2.5 times the crystallization time for Example 1. Example 1.2 showsthat repeating Example 1.1 except with a first reaction mixturecomprising the seeds provides crystalline MCM-56. Example 3 shows thatorder of seed addition for the first reaction mixture does not adverselyaffect the outcome, and that the MCM-56 seeds may be as-synthesized.Example 3.1 compared to Example 3 demonstrates that crystallization issignificantly slower without forming the first reaction mixture requiredof the present method. Example 4.1 compared to Example 4 demonstratesthat crystallization is significantly slower without forming the firstor second reaction mixture required of the present method.

Example 6

To formulate catalyst comprising “ex-situ seeded” MCM-56 manufactured bythe present improved process, 60 parts MCM-56 product recovered fromExample 1 (100% solids basis) was combined with 40 parts UOP Versal 300™pseudoboehmite alumina (100% solids basis). The combined dry powder wasplaced in a lab scale Lancaster Muller and mixed for 30 minutes.Sufficient water was added during the mixing to produce an extrudablepaste. The extrudable paste was formed into 1/20″ quadrulobe extrudateusing a 2 inch laboratory Bonnot extruder. The extrudate was driedovernight at 121° C. in an oven. The dried extrudate was heated at arate of 2.4° C. per minute to 538° C. and held for 3 hours under flowingnitrogen. The extrudate was then cooled to ambient temperature andhumidified with saturated air overnight. The humidified extrudate wasexchanged with 5 milliliters of 1 N ammonium nitrate per gram ofcatalyst for 1 hour. The ammonium nitrate exchange was repeated withfresh ammonium nitrate. The ammonium exchanged extrudate was then washedwith 5 volumes deionized water per volume of extrudate to removeresidual nitrate. The washed extrudate was dried overnight in an oven at121° C. The extrudate was then calcined in a nitrogen/air mixture at thefollowing conditions. The extrudate was ramped from ambient temperatureto 426° C. in a 1% O₂/99% N₂ mixture at a heating rate of 28° C. perhour and held at 426° C. for 3 hours. The temperature was then increasedto 482° C. at a rate of 28° C. per hour and held at 482° C. for anadditional 3 hours. At 482° C. the O₂ was increased in stages to 7.6%O₂. The extrudate was held at 482° C. in the 7.6% O₂/92.4% N₂ stream foran additional 3 hours. The temperature was then raised to 534° C. at arate of 28° C. per hour. The percentage of O₂ was gradually increased to12.6% O₂, and the extrudate was held at 534° C. in 12.6% O₂ for 12hours. The extrudate was then cooled to room temperature.

The catalyst comprising MCM-56 manufactured in this Example 6 wascharacterized by measuring the BET surface area, concentration of sodiumas determined by inductively coupled plasma (ICP) by a commonly knownmethod. Alpha Activity (hexane cracking) was determined as described inU.S. Pat. No. 3,354,078.

Examples 7, 8, 9, and 10

Three additional catalysts were formulated as in Example 6, except thatone comprised 60 wt. % MCM-56 and 40 wt. % alumina (Example 7), anothercomprised 80 wt. % MCM-56 and 20 wt. % alumina (Example 8), and anothercomprised 20 wt. % MCM-56 and 80 wt. % alumina (Example 9) and anothercomprised 65 wt. % MCM-56 and 35 wt. % alumina (Example 10). Thecatalysts comprising MCM-56 manufactured in these Examples werecharacterized by measuring the BET surface area, concentration of sodiumas determined by ICP, and Alpha Test activity (hexane cracking) as it iscommonly known in the patent literature.

Example 11

In similar fashion, a 60 wt. % MCM-56, 40 wt. % alumina catalyst wasformulated according to Example 6 using “in-situ seeded” MCM-56 crystalprepared according to Example 3.

Example 12

In similar fashion, a 100 wt. % MCM-56, 0 wt. % alumina catalyst wasformulated according to Example 6 using a “non-seeded” MCM-56 crystalprepared according to Example 5.

Example 13

In similar fashion, a 80 wt. % MCM-56, 20 wt. % alumina catalyst wasformulated according to Example 6 using a “non-seeded” MCM-56 crystalprepared according to Example 5.

Example 14

In similar fashion, a 80 wt. % MCM-56, 20 wt. % alumina catalyst wasformulated according to Example 6 using a “non-seeded” MCM-56 crystalprepared according to Example 5. 0.05 wt. % polyvinyl alcohol was usedas an extrusion aid in the formulation process.

Example 15

To further test the catalysts of Examples 6 through 14, 0.5 gram ofextrudate catalyst was loaded in a wire mesh screen basket along with 12grams of quartz chips. The basket and contents were dried overnight (˜16hours) in an oven at 260° C. The basket was then loaded in a 300 cc Parrautoclave. The autoclave was sealed and purged free of air with flowingnitrogen. The autoclave was heated to 170° C. and purged with 100 sccmof nitrogen for 2 hours. The autoclave agitator was set to 500 rpm.Then, 156.1 grams of benzene was transferred to the autoclave, and thetemperature was set to 130° C. at an agitation speed of 500 rpm for 1hour. After 1 hour, 28.1 grams of propylene was transferred to theautoclave using a 75 cc Hoke transfer vessel. A constant head pressurewas maintained on the autoclave using a nitrogen blanket. Liquid productsamples were taken at 30, 60, 90, 120 and 180 minutes. The liquidsamples were analyzed on an Agilent 5890 GC. The GC data was fitted to a2^(nd) order kinetic model. The 2^(nd) order kinetic rate constant forthe conversion of benzene and propylene was calculated along with theratio of diisopropylbenzene (DIPB) to cumene and triisopropylbenzene(TRIPB) to cumene at 3 hours time-on-stream.

Table 6 and FIGS. 1, 2, 3 and 4 summarize the physical and catalyticproperties of the “ex-situ seeded” MCM-56 catalyst compositions(Examples 6 to 10), the “in-situ” seeded MCM-56 catalyst compositions(Example 11), and the “non-seeded” MCM-56 catalyst compositions(Examples 12 to 14).

FIG. 1 shows that the DIPB/IPB ratio generally decreases as the MCM-56content in the extrudate decreases from 100% to 20%. FIG. 2 clearlyshows that the heavy components (TR1-IPB's), which require an additionaland difficult transalkylation reaction (in commercial operation) back tocumene, are reduced when the MCM-56 content is less than 80 wt. % andpreferably less than 65 wt. % and most preferably less than 60 wt. %.

FIG. 3 shows that we are able to maintain a 2nd order rate constant forthe alkylation of propylene with benzene k₂ greater than or equal to0.20 even though the zeolite content is reduced from 100% to 20%. FIG. 4shows that the ratio of DIPB/TR1-IPB is relatively constant over therange of MCM-56 content of 20 to 100 wt. %. All of the “ex-situ” seededMCM-56 data in the Figures are in the Tables.

TABLE 6 Example 6 MCM-56 (wt. %), Al₂O₃ (wt. %) 40/60 40/60 40/60 SODIUM(wt. %) 0.0269 0.017 0.0215 Alpha Activity 230 300 220 Rate Constant (1)287 441 397 DIPB/Cumene (2) 14.6 14.5 16 TRIPB/Cumene (3) 1.37 1.3 1.66TRIPB/DIPB 0.09 0.09 0.10 BET Surface Area (m²/g) 389 379 390 ZeoliteSurface Area (m²/g) 110 95 99 Matrix Surface Area (m²/g) 279 284 290Example 7 MCM-56 (wt. %), Al₂O₃ 60/40 60/40 60/40 60/40 (wt. %) SODIUM(wt. %) NA NA 0.0362 0.0435 Alpha Activity 220 NA 240 270 Rate Constant(1) 0.318 0.358 360 0.414 0.348 0.392 0.447 0.227 0.289 0.439DIPB/Cumene (2) 14.9 17.2 17 15.6 15.7 15.4 17.0 16.4 16.0 18.1TRIPB/Cumene (3) 1.34 1.89 1.86 1.85 1.51 1.59 1.48 1.58 1.61 2.11TRIPB/DIPB 0.09 0.11 0.11 0.12 0.10 0.10 0.09 0.10 0.10 0.12 BET SurfaceArea (m²/g) 396 428 382 394 Zeolite Surface Area (m²/g) 144 157 136 151Matrix Surface Area (m²/g) 252 271 246 243 Example 8 Example 9 Example10 MCM-56 (wt. %), Al₂O₃ (wt. %) 80/20 20/80 65/35 SODIUM (wt. %) 0.0376NA NA Alpha Activity 200 110 290 Rate Constant (1) 0.199 0.24 0.4430.141 0.448 0.160 0.484 DIPB/Cumene (2) 16.1 12.2 12.2 17.3 14.4 17.113.9 TRIPB/Cumene (3) 1.61 1.22 1.14 1.90 1.29 1.88 1.19 TRIPB/DIPB 0.100.10 0.09 0.11 0.09 0.11 0.09 BET Surface Area (m²/g) 435 342 425Zeolite Surface Area (m²/g) 212 34 171 Matrix Surface Area (m²/g) 223308 255

Example 16

MCM-56 zeolites were manufactured using the seeded zeolite synthesis, asdescribed above in Example 1. The MCM-49 zeolite was also manufacturedusing seeds and formulated into catalyst as in Example 8. The catalystscomprising MCM-56 were formulated into catalysts as in Examples 16 to19. These formulated catalysts were then placed in a testing apparatusto determine their selectivity for diethylbenzene (DEB) by-products (asmeasured by the sum of the diethylbenzenes divided by the ethylbenzene(EB)). The testing apparatus consisted of a feed system for supplyingbenzene (B) and ethylene (E); a mixing zone to ensure proper dissolutionof the ethylene in the benzene; a reactor consisting of ½″ stainlesssteel tubing; a heating element capable of maintaining a +/−4° C. lineartemperature profile; an in-line sampling valve for automated samplecollection; and a GC containing an FID for determining the relativeamounts of hydrocarbon species present in the effluent. Approximatelyone gram of catalyst is packed in the reactor with a small particle sizesilicon carbide as a diluent to ensure good flow distribution. Thereactor also contains a 1/16″ internal thermal couple to determine theinternal temperature profile (5 points). The temperature and pressure ofthe testing was set nominally to be 180° C. at the inlet of the reactorbed and about 500 psig at the outlet of the reactor bed. The benzene toethylene mole ratio (B:E) was nominally set to 19. The total flow wasadjusted to achieve conversions less than 100%. Five different catalystswere tested and the results are shown for Examples 16.1 through 16.5.The conversion is a measure of ethylene conversion (ethylene converteddivided by ethylene fed).

Example 16.1

In a comparative example, an 80 wt. % MCM-49, 20 wt. % alumina bindermaterial was tested over a range of conversions. The selectivity isshown in FIG. 5 and Table 7.

Example 16.2

A 40 wt. % seeded MCM-56, 60 wt. % alumina binder material was testedover a range of conversions. The selectivity is shown in FIG. 5 andTable 7.

Example 16.3

A 60 wt. % seeded MCM-56, 40 wt. % alumina binder material was testedover a range of conversions. The selectivity is shown in FIG. 5 andTable 7.

Example 16.4

An 80 wt. % seeded MCM-56, 20 wt. % alumina binder material was testedover a range of conversions. The selectivity is shown in FIG. 5 andTable 7.

Example 16.5

A 20 wt. % seeded MCM-56, 80 wt. % alumina binder material was testedover a range of conversions. The selectivity is shown in FIG. 5 andTable 7.

TABLE 7 Ethylene Selectivity B:E wt DEB/ Conversion (DEB/EB) (molar) wtEB Ex. 16.1 50.2% 0.035 20.33 3.7% Ex. 16.1 26.8% 0.025 18.66 2.5% Ex.16.1 18.6% 0.0206 18.9 2.0% Ex. 16.1 23.5% 0.02266 19 2.3% Ex. 16.227.4% 0.02205 19.17 2.2% Ex. 16.2 16.7% 0.01787 18.16 1.7% Ex. 16.213.8% 0.0162 18.57 1.6% Ex. 16.2 16.7% 0.0166 18.6 1.6% Ex. 160.3 55.9%0.034854 20.56 3.8% Ex. 16.3 34.5% 0.0254 19.12 2.6% Ex. 16.3 22.5%0.0197 19.03 2.0% Ex. 16.3 26.3% 0.0212 19.14 2.1% Ex. 16.4 61.8%0.04525 20.8 5.0% Ex. 16.4 44.7% 0.03611 19.4 3.7% Ex. 16.4 29.0%0.02665 19.25 2.7% Ex. 16.4 30.7% 0.0269 19.35 2.7% Ex. 16.5 10.2%0.019239 18.45 1.9% Ex. 16.5 6.1% 0.018582 17.67 1.7% Ex. 16.5 4.9%0.019 18 1.8% Ex. 16.5 5.7% 0.0178 18 1.7%

Table 7 Shows the selectivity for each example catalyst at differentconversion levels. The selectivity is a measure of the sum of the DEBproducts divided by the EB product. It is also adjusted by the inverseproportion of the B:E ratio to ensure that the data is comparable.

FIG. 5 shows a plot of the ethyl benzene selectivity for each exampleversus the ethylene conversion. From this plot, several importantconclusions can be drawn:

-   -   The seeded MCM-56 has a very high conversion compared to the        MCM-49.    -   By lowering the zeolite content, some activity is sacrificed but        with the advantage of lower selectivity of DEB by-products.        Operation with this catalyst reduces utility consumption because        less distillation is required with a lower DEB concentration.    -   The advantage of lower zeolite content is limited to a        crystal/binder weight range below 80/20 and above 20/80 because,        at or below the 20/80 level, the conversion is too low to be        commercially useful (<10% compared to >10% for the rest of the        catalysts).

All patents, patent applications, test procedures, priority documents,articles, publications, manuals, and other documents cited herein arefully incorporated by reference to the extent such disclosure is notinconsistent with this invention and for all jurisdictions in which suchincorporation is permitted.

When numerical lower limits and numerical upper limits are listedherein, ranges from any lower limit to any upper limit are contemplated.

While the illustrative embodiments of the invention have been describedwith particularity, it will be understood that various othermodifications will be apparent to and may be readily made by thoseskilled in the art without departing from the spirit and scope of theinvention. Accordingly, it is not intended that the scope of the claimsappended hereto be limited to the examples and descriptions set forthherein but rather that the claims be construed as encompassing all thefeatures of patentable novelty which reside in the present invention,including all features which would be treated as equivalents thereof bythose skilled in the art to which the invention pertains.

We claim:
 1. A process for selectively alkylating benzene with analkylating agent to form a monoalkylated benzene, comprising: (i)producing synthetic porous crystalline MCM-56 material by a methodcomprising the steps of: a) preparing a first reaction mixturecontaining sources of alkali or alkaline earth metal (M) cation, anoxide of a trivalent element X, an oxide of a tetravalent element Y,zeolite seed crystals, and water, said first reaction mixture having acomposition in terms of mole ratios of oxides within the followingranges: YO₂/X₂O₃=5 to 35; H₂O/YO₂=10 to 70; OH⁻/YO₂=0.05 to 0.20;M/YO₂=0.05 to 3.0; said first reaction mixture further comprisingex-situ MCM-56 zeolite seed crystals in an amount from greater than orequal to 0.05 wt. % to less than or equal to 5 wt. %, based on theweight of said first reaction mixture; b) adding directing agent R tothe reaction mixture of step a) to form a second reaction mixture,having said directing agent R in terms of a mole ratio within thefollowing range: R/YO₂=0.08 to 0.3; c) crystallizing said secondreaction mixture of step b) under conditions of temperature of fromabout 90° C. to about 175° C. and a time for less than 90 hours to forma product mixture comprising crystals of a seeded MCM-56 material andless than 10 wt. % non-MCM-56 impurity crystals based on the totalweight of said MCM-56 crystals in said product mixture, as identified byX-ray diffraction; and d) separating and recovering at least a portionof said crystals of said seeded MCM-56 material from said productmixture of step c), wherein said zeolite seed crystals and said crystalsof said seeded MCM-56 material have an X-ray diffraction pattern asshown in Table 1 below: TABLE 1 Interplanar d-Spacing (Angstroms)Relative Intensity 12.4 ± 0.2  vs 9.9 ± 0.3 m 6.9 ± 0.1 w 6.4 ± 0.3 w6.2 ± 0.1 w 3.57 ± 0.07 m-s 3.44 ± 0.07 vs

(ii) combining said seeded MCM-56 crystals with an alumina binder in acrystal/binder weight ratio from about 20/80 to about 80/20 to form acatalyst composition; and (iii) contacting a feedstock containing saidbenzene and said alkylating agent with said catalyst composition undereffective alkylation conditions to form a product comprising saidmonoalkylated benzene, said alkylation conditions including atemperature of from about 0° C. to about 500° C., a pressure from about0.2 to about 25000 kPa-a, a molar ratio of said benzene to saidalkylating agent of from about 0.1:1 to about 50:1, and a feed weighthourly space velocity (WHSV) based on said alkylating agent of fromabout 0.1 to about 500 hr⁻¹, wherein said alkylating agent is selectedfrom the group consisting of ethylene, propylene and mixtures thereof.2. The process of claim 1, wherein said product in step d)(iii) furthercomprising dialkylated benzene and trialkylated benzene, and the weightratio of trialkylated benzene to dialkylated benzene is in the rangefrom 0.08 to 0.12.
 3. The process of claim 1, wherein said monoalkylatedaromatic compound is ethylbenzene when said alkylating agent isethylene.
 4. The process of claim 1, wherein said monoalkylated aromaticcompound is cumene when said alkylating agent is propylene.
 5. Theprocess of claim 1, wherein said amount of said zeolite seed crystals insaid first reaction mixture is greater than or equal to 0.10 wt. % toless than or equal to 3 wt. %, or greater than or equal to 0.50 wt. % toless than or equal to 3 wt. %, based on the weight of the first reactionmixture.
 6. The process of claim 1, wherein said directing agent R isselected from the group consisting of cyclopentylamine, cyclohexylamine,cycloheptylamine, hexamethyleneimine (HMI), heptamethyleneimine,homopiperazine, and combinations thereof.
 7. The process of claim 1,wherein said directing agent R comprises hexamethyleneimine (HMI), Xcomprises aluminum and Y comprises silicon.
 8. The process of claim 1,wherein said mixture of step c) comprises less than or equal to about 5wt. % non-MCM-56 impurity crystals, based on the total weight of saidMCM-56 crystals in said product mixture, as identified by X-raydiffraction.
 9. The process of claim 1, wherein said first reactionmixture has a composition in terms of mole ratios of oxides within thefollowing ranges: YO₂/X₂O₃=15 to 20; H₂O/YO₂=15 to 20; OH⁻/YO₂=0.1 to0.15; M/YO₂=0.11 to 0.15; said first reaction mixture further comprisingzeolite seed crystals in an amount from greater than or equal to 1 wt.%to less than or equal to 3 wt. %, based on the weight of said firstreaction mixture; and step b) comprises adding (HMI) as said directingagent R to said first reaction mixture to form a second reaction mixturehaving HMI in terms of a mole ratio within the range of: HMI/YO₂=0.1 to0.2.
 10. The process of claim 1, wherein said conditions ofcrystallizing step c) include crystallizing said second reaction mixturefor less than 40 hours.
 11. The process of claim 1, wherein saidconditions of crystallizing step c) include a temperature of from about125° C. to about 175° C. for from about 20 to about 75 hours.
 12. Theprocess of claim 1, wherein said second reaction mixture of step b) hasa solids content of less than 30 wt. % based on the weight of saidsecond reaction mixture.
 13. The process of claim 1, wherein saidcrystals said seeded of MCM-56 material from step d) are thermallytreated by heating at a temperature of from about 370° C. to about 925°C. for a time of from 1 minute to about 20 hours to form said seededMCM-56 crystals of step d)(ii), wherein said seeded MCM-56 crystalsafter thermal treatment have an X-ray diffraction pattern as shown inTable 2 below: TABLE 2 Interplanar d-Spacing (Angstroms) RelativeIntensity 12.4 ± 0.2  vs 9.9 ± 0.3 m 6.9 ± 0.1 w 6.2 ± 0.1 w 3.55 ± 0.07m-s 3.42 ± 0.07 vs.


14. The process of claim 1, wherein when said alkylating agent isethylene, said alkylation conditions include a temperature of from about150° C. to about 300° C., a pressure from about 2000 kPa-a to about 5500kPa-a, a molar ratio of benzene to ethylene of from about 0.5:1 to about30:1, and a feed weight hourly space velocity (WHSV) based on theethylene of from about 0.1 hr⁻¹ to about 20 hr⁻¹.
 15. The process ofclaim 1, wherein when said alkylating agent is propylene, saidalkylation conditions include a temperature of up to about 250° C., apressure from about 1000 kPa-a to about 3000 kPa-a, a feed weight hourlyspace velocity (WHSV) based on the propylene of from about 0.1 hr⁻¹ toabout 250 hr⁻¹, and a ratio of benzene to propylene from about 0.5:1 toabout 30:1 molar.
 16. The process of claim 9, further comprising thestep of: (e) contacting said dialkylated benzene and trialkylatedbenzene with additional benzene in the presence of a transalkylationcatalyst to produce additional rnonoalkylated benzene.
 17. The processof claim 16, wherein said transalkylation catalyst comprises at leastone crystalline molecular sieve selected from the group consisting ofzeolite Beta, zeolite Y, mordenite, an MCM-22 family material, andmixtures thereof.
 18. The process of claim 17, wherein said MCM-22family material has an X-ray diffraction pattern including d-spacingmaxima at 12.4±0.25, 6.9±0.15, 3.57±0.07 and 3.42±0.07 Angstroms. 19.The process of claim 17, wherein said zeolite Y includes Ultrastable Y(USY) and Rare earth exchanged Y (REY).
 20. The process of claim 17,wherein said mordenite includes TEA-mordenite.